Abstract: The experiment had the aim of investigate the responses provoked by the progressive water deficit and evaluate as the rehydration can to contribute to the recovery of the leaf relative water content, plant water content, nitrate reductase enzyme activity, as well as changes in the nitrogen compounds as free ammonium, total soluble amino acids and total soluble proteins in Glycine max (L.) Merril cultivar Sambaiba. The experimental design was at randomized entirely factorial, with 2 water conditions (control and stress/ rehydration) and 5 evaluation points (0, 2, 4, 6th day under stress and 7th day under rehydration). The nitrate reductase activity had accumulated reduction of 70% after 6 days of water deficit and the rehydration promoted increase of 96% in this parameter. The total soluble proteins were reduced at 20.7% in the 6th day of water restriction and after the rehydration were showed increase of 43% in this variable. The results showed with this cultivar submitted the water restriction reveal that occurr significant reductions in the leaf relative water content, plant water content, nitrate reductase enzyme activity, free ammonium and total soluble proteins, however, was showed increase in the free amino acids levels. The leaf relative water content, nitrate reductase enzyme activity and total soluble proteins were recovery after the rehydration.